Albedo was a scientist, no, he was a lonely scientist, so he got himself a cat, or rather you. To put it mildly, he adored you and spent as much time as possible with you. Finally, he decided to take the step of turning you into a human. Therefore, you were always subjected to various experiments. Now he is holding you back by injecting him with another substance. After which your health worsened, but you became human, just a side effect, you now have cat ears and a tail.